This invention relates to hydraulic actuators. Specifically, this invention relates to a bi-directional hydraulic actuator.
Hydraulic actuators are commonly used on equipment today. Hydraulic actuators work because a force or pressure in a closed fluid system that is applied to one point is transferred to another point in the same closed system. This is typically accomplished by using an incompressible or nearly incompressible fluid. The force that is applied at one point in the system can be multiplied at another point in the system to create a very powerful force which can be used for moving mechanical devices.
One such bi-directional hydraulic actuator is shown in U.S. Pat. No. 6,626,055. In this patent the two pressure chambers receive a pressurizing fluid in either of the pressure chambers which causes the rack to move in the direction away from the pressure of the pressurizing fluid. As the rack moves, the teeth engage the teeth of a pinion gear. Thus, the linear movement of the rack creates a rotational movement of a pinion which rotates around a point in the center of the pinion.
One problem with this type of hydraulic actuator is that in order to have bi-directional motion of the rack, the pistons must be located at opposite ends of one another and thus creating a relatively long actuator assembly. Therefore, it is desirable to have a hydraulic actuator which creates bi-directional motion by having a shorter rack assembly for the same relative amount of rotational movement.
The primary objective of the present invention is to provide an improved hydraulic actuator.
Another objective of the present invention is to provide an actuator which is enclosed within a housing and thus increases the life of the actuator.
A further objective of the present invention is to create an actuator which uses rack and pinion gearing to create rotational movement on one or more mechanical arms.
A still further objective of the present invention is to create a hydraulic actuator in which greater force can be created in one direction than is created using the actuator in the opposite direction.
Yet another objective of the present invention is the provision of a hydraulic actuator which is economical to manufacture, durable in use, and efficient in operation.
A still yet another objective of the present invention is to provide an improved method of creating bi directional linear motion in a hydraulic actuator using a shorter piston assembly within an enclosed housing.
One or more of these or other objects of the invention will be apparent from the specification and claims that follow.